/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.shardingsphere.mode.node.path.engine.generator;

import lombok.RequiredArgsConstructor;
import org.apache.shardingsphere.infra.util.reflection.ReflectionUtils;
import org.apache.shardingsphere.mode.node.path.NodePath;

import java.util.Optional;

/**
 * Node path segment.
 */
@RequiredArgsConstructor
public final class NodePathSegment {
    
    private final String input;
    
    /**
     * Get segment literal.
     *
     * @param nodePath node path
     * @return segment literal
     */
    public Optional<String> getLiteral(final NodePath nodePath) {
        Optional<String> variableName = new NodePathVariable(input).findVariableName();
        if (variableName.isPresent()) {
            Object variableValue = ReflectionUtils.getFieldValue(nodePath, variableName.get()).orElse(null);
            if (null == variableValue) {
                return Optional.empty();
            }
            if (variableValue instanceof NodePath) {
                return Optional.of(NodePathGenerator.toPath((NodePath) variableValue));
            }
            return Optional.of(variableValue.toString());
        }
        return Optional.of(input);
    }
}
